jQuery .css() Method – Get or Set Inline Styles Dynamically

Introduction – Why Use the .css() Method in jQuery?

Changing styles dynamically is essential for interactive and responsive user interfaces. The jQuery .css() method lets you get or set CSS properties directly on elements. It offers full control over inline styles for hover effects, themes, animations, validation, and more—all with simple, readable syntax.

In this guide, you’ll learn:

• How to use .css() to get and set styles
• Syntax for single and multiple property manipulation
• How to compute and use dynamic styles
• Best practices and real-world examples

What is the .css() Method?

The .css() method in jQuery can read or write one or multiple CSS property values.

Syntax:

$(selector).css(propertyName); // GET
$(selector).css(propertyName, value); // SET
$(selector).css({ prop1: val1, prop2: val2 }); // SET multiple

Example 1 – Set a Single Style

$("#banner").css("background-color", "lightblue");

Explanation:

• Selects the element with ID #banner
• Sets its inline background-color style to lightblue

Perfect for real-time style changes like themes, alerts, or highlights.

Example 2 – Set Multiple Styles at Once

$(".box").css({
  "width": "200px",
  "height": "150px",
  "border": "2px solid #333"
});

Explanation:

• Applies multiple styles to every .box element
• Each CSS property is written as a string key in camelCase or dash format

Cleaner and faster than writing multiple .css() calls.

Example 3 – Get a CSS Property Value

let color = $("#title").css("color");
console.log(color);

Explanation:

• Retrieves the current computed color of #title
• Logs it in the browser console (e.g., rgb(0, 0, 0))

Useful for reading current styles or computing conditional logic.

Example 4 – Use .css() with Calculations

$(".box").each(function() {
  let w = $(this).width(); // get numeric width
  $(this).css("height", w + "px"); // set height equal to width
});

Explanation:

• Makes each .box a perfect square
• Combines .width() and .css() dynamically

Example 5 – Inline Animation with .css()

$("#alert")
  .fadeIn(300)
  .css("background-color", "yellow")
  .delay(1000)
  .fadeOut(300);

Explanation:

• Combines animations and inline styling
• Great for temporary highlights or notices

Common Pitfalls

Best Practices

Use .addClass() for reusable styles; use .css() for dynamic overrides
When setting numeric values, always include units (e.g., px, %, em)
Use computed values with .width(), .height(), .position() to adapt layout

let left = $("#ref").position().left + 50;
$("#tooltip").css("left", left + "px");

Real-World Use Cases

Summary – Recap & Next Steps

The .css() method gives you powerful control over inline styling, allowing dynamic, conditional, and responsive adjustments in your jQuery-enhanced interfaces.

Key Takeaways:

• Use .css() to get or set inline styles
• Use object format for multiple styles at once
• Combine with measurements and events for full layout control
• Prefer .addClass() when possible for better maintainability

Real-World Relevance:
Used across interactive dashboards, modals, form validators, and dynamic themes, .css() is essential in customizing UI behavior in real-time.

FAQ – jQuery .css() Method

Can I set multiple styles at once?

Yes! Use an object:

$("#box").css({ width: "100px", height: "100px" });

Is .css() better than using classes?

No. Use classes (.addClass()) for scalable styles. Use .css() for temporary or conditional tweaks.

What if I forget the unit in .css("width", 100)?

It won’t work properly. Always use units like "100px".

Can .css() get styles defined in CSS files?

Yes, it gets computed styles, including those set via external CSS.

How do I remove a style set with .css()?

Use .css("property", ""):

$("#box").css("border", "");